Arc extinguishing device



Feb. 17, w BOEHNE ARC EXTINGUISHING DEVICE Filed Sept. 17, 1945 HisAttorney.

Patented Feb. 17, 1948 ARC EXTINGUISHING DEVICE Eugene W. Boehne. DrexelHill, I'a., assl nor to General Electric Company,

New York a corporation of Application September 17, 1945, Serial No.816,905

My invention relates to improvements in arc extinguishing devices andmore particularly to arcextinguishing devices for circuit breakers andespecially circuit breakers for interrupting unidirectional currentshaving a high rate 01 rise.

Since unidirectional currents do not periodically pass through zerovalues as do alternating currents. the problem of circuit interruptionis more diillcult and especially so with so-called anode circuitbreakers used in controlling arc rectiflers because of the high rate ofrise of current when'an arc-back occurs. Arc extinguishin: devices forsuch circuit breakers are therefore subject to severe duty. Sincevaporized metal in the are stream tends to maintain and stabilize theare, it is necessary vapor in the are at a minimum. The metallic contentof the arc stream is dependent principally upon metal derived from thearc runners. It is therefore important that the ends of the arc incontact .with the arc runners be kept moving continuously in order toavoid heat concentration and the consequent high vaporizing action andalso that are runners be made of metal having a high meltingtemperature. Since the metallic contentof the arc is built up in the endportions .of the are where it is attached to the arc runners, it isimportant to pocket these metal-laden end portions apart from thecentral or body portion of the are in order to keep the metalliccontamination of the central portion of the arc to a minimum. If the arcportions are thus pocketed, then it is necessary to exhaust themetal-laden vapors of the end portions of the arc in sucha way that theycannot mingle with the exhaust of the central portion of the arc.Otherwise a conducting path may be created over the top 01' the arcextinguishing device with consequent failure to interrupt. In additionto the technical factors involved. there are also the important economicfactors of cost, simplicity and flexibility of application.

An object of my invention is to provide for circuit breakers an improvedare extinguishing device wherein the formation of metallic vapor fromthe arc runners is minimized. Another object of my invention is toprovide an improved arc extinguishing device wherein the end portions ofthe arc are pocketed in compartments apart from a compartment for thecentral or body portion of the arc in order to reduce the metallic vaporcontent thereof. Still another ob- Ject of my'invention is to preventany reforma- Claims. (Cl. 200-147) to keep the metal 'ing device inconsequence of a mingling of the exhaust portions of the ends of the arcand the central portion thereof. A further object of my invention is toprovide a relatively simple and economical arc extinguishing devicewhich is especially adaptable for air circuit breakers and which isreadily removable from the circuit breaker structure for replacement.inspection and repairs. These and other objects of my invention willappear in more detail hereinafter.

In accordance with my invention, I provide an improved arc extinguishingdevice comprising insulating means forming an arcing compartment wherein.an arc runner mounted near the lower edge thereof and extendinggenerally upwardly is provided with an end which is curved through anangle such as to keep the end of the arc moving continuously untilinterruption occurs. Also in accordance with my invention, I provide an50 improved arc extinguishing device comprising intion of the are at thetop of the arc extinguishb5 sulating means forming three compartments.two of which are provided with are runners of electric currentconducting material with their base portions extending into the thirdcompartment.

Further in accordance with my invention. I provide the insulating meanswith an elongated opening between each of the compartments in which therunners are mounted and the third compartment whereby an are attached tothe runners can be continuous from the arc runner in one of the twocompartments into the third compartment and onto the arc runner in theother of the two compartments in order to minimize the metallic vaporcontent oi the central portion of the are.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying sheet of drawings.and its scope will be pointed out in the appended claims.

In the accompanying drawing. Fig. 1 is a side elevation of an arcextinguishing device embodying my invention with parts broken away forclearness; Fig. 2 is a perspective view of the embodiment of myinvention shown in Fig. 1 with parts broken away for clearness; and Fig.3 is a sectional view on the line 3-3 of Fig. 1.

In Fig. 1, I have illustrated an embodiment of my invention as appliedto a circuit breaker such as that disclosed in Letters Patent 01' theUnited States 2,329,003, issued September 7, 1943. Since the circuitbreaker itself forms no part of my invention, only such parts of thecircuit breaker are shown as are pertinent to an understanding of theapplication of my invention. Thus, in

v ing material and a filler .8 prevent sidewise movement of this fillerFig. 1 the circuit breaker is shown as including an upper terminal studassembly I on which is movably supported a plurality of relativelymovable main stationary contacts 2 and a stationary arcing contact 3.Cooperating with the main stationary contacts 2 is a movable maincontact 3 and with the stationary arcing contact 3 is a movable arcingcontact 5. Both the movable main contact 4 and the arcing contact 5 areconnected to the lower terminal stud, not shown, of the circuit breakerby a suitable flex ble lead 6.

In accordance with my invention, I provide an improved arc extinguishingdevice which compri es insulating means forming three compartments. Asshown, the insulating means comprises ihree spaced p ates 1, 8 and 9 ofsuitable insulating material forming two compartments which are open atthe top and front edges but are closed at the rear edge by insulatingspacers l and I l. Near the base of the compartment between theintermediate insulating plate 8 and the outside insulating plate 9, Imount two spaced divergent arc runners 2 and i3 of suitable electriccurrent conducting material so shaped that their bases l4 and Irespectively extend into the compartment between the intermediateinsulating pla e 8 and the outside insulating plate 1. In order totransfer to the arc runners I2 and I3 an arc drawn between thecooperating arcing contacts 3 and 5 upon separation thereof. thestationary arcing contact 3 may be positioned directly on the arc runnerl2 or in suitable conductive relation therewith, and the base |5 of-thearc runner I3 is so positioned as to receive the arc from the movablearcing contact 5 upon movement thereof away from the contact 3. The arerunner I2 is mounted directly on the terminal studiassembly andthe'space between the arc runner and the insulating spacers l0 and H isoccupied by fillers I6 and H of suitable insulatl8 which slides behindthe arc runner from the side. The plates I arliad With this arrangement,the parts l6, l1 and 8 remain on the upper stud assembly I when the arcchute .is removed. Bolts l9 passing through insulating bushings 20 serveto hold the plates 1, 8-and 9 and the spacers Ill and H in the assembledrelation,

The are runner I3 is supported adjacent the lower front edge of the arcchute on a spacer 22 of suitable insulating material between the plates1 and 8 and, a spacer 2| of suitable insulating material between theplates 8 and 3 with intervening baflle plates 23 of suitable insulatingmaterial between the spacer and the outside plates. Bolts 24 passingthrough insulating bushings 25 serve to maintain the assembly of thespacers 2| and 22, the baffle plates 23 and the insulating plates I, 8and 9. The lower end 26 of the arc runner l3 extends downward over thespacers 2| and 22 and is provided with a terminal portion 21 from Whch aconductor 21' leads to the lower terminal stud. not shown, of thecircuit breaker.

In accordance with my invention, to avoid heat concentration andconsequent burning of the arc runner l3 at the upper end 28 thereof, Iso curve this end as to keep the root of the are attached theretocontinuously moving. As shown, the angle of curvature is approximately180 since this amount also helps to lock the runner in place on itssupporting spacer 2|. However, for the purpose of keeping the root ofthe arc continuously moving, if the runner curves sufiiciently to extendsomewhat beyond the line of tangency to a vertical plane, the desiredaction will be obtained. In general, a curvature of approximately willserve the purpose. In order to obtain arc movement without the use ofblowout coils, the arc runners l2 and I3 are preferably made oielectromagnetic electric current conducting mater al such as steel whichhasa melting point sufficiently high to minimize the metallic vaporcontamination of the arc compartments whereby to expedite arcextinction.

Further in accordance with my invention, in order to minimize thecontamination of the central or body portion of the are by the metallicvapor formed at the end portions of the are, I provide means forisolating the end portions of the are from the central or body portionthereof. Thus, in accordance with my invention, I provide means fordividing the compartment between the plates 8 and 9 into two compartmentdivisions or parts whereby to maintain the ends of the arc in thecompartment between theplates 8 and 9 and the central or body portion ofthe arc in the compartment between the plates I and 8 as indicated bythe dash-dot line 29 in Fig. 2. As sh wn, this means comprises a barrier3 0 of suitable insulating material extending upwardly from the bases l4and i5 of the arc runners in the compartment between the intermediateplate 8 and the outside plate 9. In order tohave the body portionof thearc in the compartment .between the outside plate 1 and the intermediateplate 8, I provide intercommunicating means between this compartmentand'the two parts of the compartment between the intermediate plate 8and the outside plate 9. As shown, this intercompartment communicatingmeans is provided in the intermediate plate 8 as two elongated divergentopenings 3| and 32 extending from the ba e 33 of the barrier 30 andrespectively above the arc runners |2 and I3 and approximately parallelthereto. By the phrase respectively above the arc runners l2 and i3, Imean that relatively to the faces of the arc runners, the openings 3|and 32 are toward the discharge openings of the arc chute. In ordertoprovide easy flow lines for the gases and to permit their beingexhausted in opposite directions, the edges 34 of the barrier 30 and itsbase portion 33 are suitably curved and I the edges of the openings 3|and 32 are suitably beveled. Also in order to present a smooth flowsurface, the base 33 of the barrier 30 is recessed at 35 to receive theedge of the intermediate plate 8 between the openings 3| and 32 therein.The barrier 3|] is held in place by suitable bolts 35 passing throughinsulating bushings 31. The intermediate plate 8 is made enough largerthan the outside plates 1 and 9 to prevent reformation of the are at thetop and front edges of the arc chute.

Assuming the circuit breaker arcing contacts 3 and 5 are closed, asshown in Fig. 1, and that the circuit breaker is opened in response toan overload condition, then an arc will be drawn between the contacts 3and 5 and this arc will be transferred from the arcing contact 5 to thebase l5 of the arc runner |3 as indicated by the dash-dot line 38 inFig. 2. Because of the interaction between the flux of the current inthe arc stream and the fluxes induced in the magnetic arc runners i2 andI3, the ends of the arc will quickly be driven into the two parts of thecompartment between the outside plate 3 and the intermediate plate 8,but the body portion of the are will remain in the compartment betweenthe intermediate plate 8 and the outside plate I.

As the ends of the are are forced upward along the arc runners l2 andii. the arc takes successive positions, one of which is indicated by thedash-dot line II, with the are passing through the openings 3i and 32.Eventually, as the 'ends of the arc reach the ends of the arc runners,the

' arc is extinguished. When the end oi the are attached to the arcrunner l3 res ches the curved portion 28 thereof, it travels down overthis curved portion and continues to move up and down on the curvedportion without producing any concentrated heating thereby reducing themetallic vapor content and the pitting or damage to the arc runner.maintained in separate compartments which are effectively isolated fromthe compartment which contains the body portion of the arc, the metalliccontent of the central portion of the arc in the compartment between theoutside plate 1 and the intermediate plate 8 is held at a minimum whichreduces the stability of the ar in consequence of the increasedresistance 01' this portion of the arc and therefore expedites the arcinterruption.

While I have shown and described my invention in considerable detail, Ido not desire to be limited to the exact arrangements shown, but seek tocover in the ap ended claims all those modifications that fall withinthe true spirit and. scope of my invention.

What I claim as new and desire to secure by Letters Patent the UnitedStates is:

1. In an arc extinguishing device for a circuit breaker havingrelatively movable cooperating arcing contacts, three spaced plates ofinsulating material forming two compartments, insulating means dividingone of said compartments into two parts, an arc runner of electriccurrent conducting material in each 01' said two parts. said devicebeing adapted to be mounted with the bases 01' said arc runners adjacentthe circuit breaker contacts for receiving an arc formed between thecontacts upon separation thereof, the

intermediate one of said plates being provided with an elongated openingabove each of said are runners whereby an are formed upon separation ofthe circuit breaker contacts can extend from the arc runner in one partof said one compartment into and through the other compartment and ontothe arc runner in the other part or said one compartment.

.2. In an arc extinguishing device for a circuit breaker havingrelatively movable cooperating arcing contacts, three spaced plates oiinsulating material forming two compartments, two spaced divergent arcrunners of electric current conducting material mounted in one of saidcompartments, said device being adapted to be mounted with the bases ofsaid arc runners adjacent the circuit breaker contacts for receiving anare formed between the contacts upon separation thereof, and means formaintaining the end por-,

tions of the arc in said one compartment and the body of the arc in theother of said compartments comprising an insulating barrier extendingupward in said one compartment from the bases of said arc runners andintercommunicating means- Since the ends of the are are two parts. anarc runner oi electric current conducting magnetic material in each orsaid two parts having its base portion extending into the other or saidcompartments, said are runners diverging irom their base portions, saiddevice being adapted to be mounted with the bases of said are runnersadjacent the circuit breaker contacts for receiving an are formedbetween the contacts upon separation thereof, the intermediate one ofsaid plates being provided with two deep divergent notches respectivelypositioned above said arc runners and interconnecting near the basesthereof whereby an are formed upon separation of said contacts canextend from the arc runner in one part of said one compartment into andthrough the other compartment and onto the arc runner in the other partof said one compartment with its extremities traveling outwardly on thearc runners under the cooperating magnetic eiiects of the arc and themagnetic arc runners.

4. In an arc extinguishing device for a circuit breaker havingrelatively movable cooperating arcing contacts, three spaced plates 01'insulating material forming two compartments, two spaced divergent arcrunners of electric current conducting material mounted in one of saidcompartments having their bases extending into the other or saidcompartments, said device being adapted to be mounted with the bases ofsaid are runners adjacent the circuit breaker contacts for receiving anare formed between the contacts upon separation thereof, and means formaintaining the end portions of the arc in said one compartment and thebody of the arc in the other of said compartments comprising aninsulating barrier extending upwardly in said one compartment from thebases of said are runners and interments provided in the intermediateone of said plates as two divergent elongated openings extending fromthe bottom of said barrier and respectively above said are runners andsaid intermediate plate extending upwardly above the top edges of theadjacent plates sufficiently to prevent the body of the are from movinginto said one compartment before the arc is extinguished.

5. In an arc extinguishing device for a circuit breaker havingrelatively movable cooperating arcing contacts, three spaced plates ofinsulating material forming two compartments, means for dividing one ofsaid compartments into two parts comprising an insulating barrierextending downwardly from the top of one of the outside plates andbetween said one outside plate and the intermediate plate, an arc runneroi! electric current conducting magnetic material in each of said twoparts having its base portion extending into the other of saidcompartments, said device being adapted to be mounted with the bases ofsaid arc runners adjacent the circuit breaker contacts for receiving anare formed between the contacts upon separation thereof, saidintermediate plate being provided with divergent elongated notchesextending outwardly from the bottom of said insulating spacer and abovethe respective are runners whereby an are formed upon separation of thecircuit breaker contacts can extend from the arc runner in one part ofsaid one compartment into and through the other compartment and onto thearc runner in the other part of said one compartment with itsextremities traveling outwardly from the arc runners under thecooperating magnetic repelling action of the arc and the magnetic arcrunners.

6. In an arc extinguishing device for a circuit breaker havingrelatively movable cooperating arcing contacts, three spaced plates ofinsulating material forming two compartments, insulating means dividingone or said compartments into two parts, an arc runner of electriccurrent conducting magnetic material in each of said two parts havingits base portion extending into the other of said compartments, said arerunners diverging irom their base portions, said device being adaptedtobe mounted with the bases of said are runners adjacent the circuitbreaker contacts or receiving an arc formed between the contacts uponseparation thereof, the intermediate one of said plates being providedwith an elongated opening above each of said are runners whereby an areformed upon separation of the circuit breaker contacts can extend fromthe arc runner in one part of said one compartment into and through theother compartment and onto the arc runner in the other part 01 said onecompartment with its extremities traveling outwardly on the arc runnersunder the cooperating magnetic effects of the arc and the magnetic arcrunners.

i. In an arc extinguishing device tor a circuit breaker havingrelatively movable cooperating arcing contacts, insulating means formingthree compartments, an arc runner of electric current conductingmaterial in each of two of said compartments, said device 1 beingadapted to be mounted with the bases oi! said are runners adlacent thecircuit breaker contacts tor receiving an are formed between thecontacts upon sepabreaker in a circuit,

said runner adjacent ration thereof, said insulating means beingprovided above the respective arc runners with an elongated openingbetween each of said two compartments and the third compartment and saidopenings communicating with each other near the bases 0! said arerunners whereby an arc formed upon separation of the circuit breakercontacts can extend from the arc runner in one of said two compartmentsinto and through the third compartment and onto the arc runner in theother of said two compartments.

8. In an arc extinguishing device for a circuit breaker havingrelatively movable cooperating arcing contacts, insulating means formingthree compartments, an arc runner of electric current conductingmagnetic material in each of two of said compartments having its baseportion extending into the third compartment,.said arc runners divergingfrom their base portions, said device being adapted to be mounted withthe bases or said are runners adjacent the circuit breaker contacts forreceiving an are formed between said contacts upon separation thereof,said insulating means being provided above the respective arc runnerswith an elongated openlag between each of said two compartments and thethird compartment, said openings-communicating with each other near thebases of said extremities traveling outwardly on the are runners underthe cooperating magnetic eflects oi the arc and the magnetic arcrunners.

9. In an arc extinguishing device for a circuit breaker havingrelatively movable cooperating arcing contacts respectively inconductive relation with terminals for connecting the circuit insulatingmeans forming two substantially parallel arc compartments, an electriccurrent conducting arc runner in one of said compartments adapted to beconnected to one or the circuit breaker terminals. said device beingadapted to be mounted with the base of the circuit breaker contacts forreceiving an are formed between the contacts upon separation thereof andsaid insulating means being provided above said runner with an elongatedintercompartment communicating openin approximately parallel to the arcrunner whereby an arc struck to said are runner upon separation of thecircuit. breaker arcing contacts will extend from the arc runner in saidone compartment through said opening intothe other compartment and tothe other of the circuit breaker terminals.

10. In an arc extinguishing device for a circuit breaker havingrelatively movable cooperating arcing contacts respectively inconductive rela= tion with terminals for connecting the circuit breakerin a circuit, insulating means forming two substantially parallel arccompartments, an insulating barrier approximately vertically dtvidingone of said compartments into two w v two electric current conductingarc runners re=- Y runners upon separation of the circuit breer arcingcontacts extends from the arc runner in one or said compartmentdivisions through one or said openings into and through the other compa-rtment and through the other or said openings into the othercompartment division to the other are runner.

EUGENE W. B0

earnestness orrrsn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 682,217 Merrick Sept. 10, 190i1,713,229 Hewlett May 14, 1929 1,836,994 Slepian Dec. 15, 1931 1,934,518Anderson Nov. "8. 1933 1,963,643 Brainard et al June 19, 1934 2,337,949Walle Dec. 28, 19%3 connected respectively formed between the contacts

